d supports both
        00:00 and 24:00 as a representation. The decimal separator can be
        either a dot or a comma.


        .. caution::

            Support for fractional components other than seconds is part of the
            ISO-8601 standard, but is not currently implemented in this parser.

        Supported time zone offset formats are:

        - `Z` (UTC)
        - `±HH:MM`
        - `±HHMM`
        - `±HH`

        Offsets will be represented as :class:`dateutil.tz.tzoffset` objects,
        with the exception of UTC, which will be represented as
        :class:`dateutil.tz.tzutc`. Time zone offsets equivalent to UTC (such
        as `+00:00`) will also be represented as :class:`dateutil.tz.tzutc`.

        :param dt_str:
            A string or stream containing only an ISO-8601 datetime string

        :return:
            Returns a :class:`datetime.datetime` representing the string.
            Unspecified components default to their lowest value.

        .. warning::

            As of version 2.7.0, the strictness of the parser should not be
            considered a stable part of the contract. Any valid ISO-8601 string
            that parses correctly with the default settings will continue to
            parse correctly in future versions, but invalid strings that
            currently fail (e.g. ``2017-01-01T00:00+00:00:00``) are not
            guaranteed to continue failing in future versions if they encode
            a valid date.

        .. versionadded:: 2.7.0
        Nr)